The aims of this study was to compare analgesic efficacy of preoperative administration of etoricoxib versus celecoxib for post-operative pain relief after arthroscopic anterior cruciate ligament reconstruction. One hundred and two patients diagnosed as anterior cruciate ligament injury will randomized into 3 groups using opaque envelope. Both patients and surgeon were blinded to the allocation. All of the patients will be operated by one orthopaedic surgeon under regional anesthesia. Each group will be given either etoricoxib 120 mg., celecoxib 400 mg., or placebo 1 hour prior to operative incision. Post-operative pain intensity, time to first dose of analgesic requirement and numbers of analgesic used for rescue pain control and adverse events will be recorded periodically to 48 hours after surgery.